Sound-reproducing device



June 11,1929. H. c. MUEgLER I soUND REPRQDUCING DEVICE -2 Sheets-Sheet 1Filed-oct. so, 192e l Himsa Jun lll, 1929. H. c. MU'ELLER v soUNDREPRODUCING4 DEVICE v Filed oct'. 30;'1926 2 sheets-sheet 2 fwlp y aswell as advantages inherent in my device,

Patented June' l1, 1929.

UNITED STATES y 1,716,458 l'PATENT OFFICE.

HERMAN C. MUELLER, 0F MIILWA'UKEE, WISCONSIN..

soUNn-nsrnonuome DEVICE.

Application led 0ctober30, 1l926. Serial N11/145,138.

My invention relates to a cone` type ofV loud speaker more especiallyintended for use in connection with a radio receiver and .has foritso'bject the provisionof a device-A of the character mentionedadaptedto reproduce the'natural .tonal quality of the directly and'wholly within the magneticl field ofthe permanent magnet.

v Another object of the invention is to provide a device wherein the'pole pieces extend substantially*- flggh with the outer. 'sides'.of thepermanent magnet and there' 'the coil.

fore beyond the sides of objects and others,

A The above enumerated will all be more fully comprehended from thefollowing detailedA descption vof the `line. 3-3 'of Figure 2 lookingin' the dif--l accompanying drawings, wherein-'- l Figure 1 isarelevation'ofmy improved cone loud speaker. v

Figure2 is a cross-section taken substan tially on the line 2-2'ofFigure 1 looking in the direction of the arrows. A

I Figure'' is a sectional view taken on the rectionof -the arrows..

Flgurel v1s an elevation of the outercone mounting with portions of. theouter ,coneand its mountings broken away. v Y

Figure 5 is a "sectional elevation of the magnets and mountings andshowing a portion of vthe holding member or plate. I=

Figure 6 isa detailview in perspective y net. The pole piecesof-theinner cone, v V

Figure 71's a d 'tail perspective view of a pole piece separating andarmature support holding memben y V -Figure 8 is a perspective view ofmy im' proved armature. .Figure 9 illustratesa modification of mydevice, with the outer cone and 'itsmount ing partially broken away andshown in section and with a portion of thel magnet holding shell beingshown.

Figure 10 is aperspective fied form of inner cone. l `The invention asdisclosed in the drawings comprises a suitable standard or s upport 15for holding the unit which is prefy 26, 27. view of modierably mountedin a suitable housing or shell g 16. The shell is provided with a baseplate" i or disc 17 shown preferably provided with anannularshoulder18'and a central open- 60 ing 19. The'plate or disc 17 adjacent to itsouter perimeter is also shown provided with anopening` 20.

- Oneside of the platel 17 has-a permanenti magnetv 21 mountedthereon;nthef jmagnet 65 with its associated parts beingheldin'place -bya cross-ball.'V 22 whichstraddl'es one leg or s1de of thepermanentmagnet 21 and .is

shown removably secured -to'l the plate or disc by screws 23. The' endsof the cross- 7.0

. bar 22 areprovided ywith suitable binding posts 24, 24, to receivethevarious lead lines; one, of the leads' or terminals fromv the outputvend vof a radio receiver being shownatf25.'4 y75 The holesin thecross-bar 22 throughv 7 whichl the Afastening screws 23 passarepreferably -provided 4with insulating washers to prevent Contact betweenthe'fas'tening screws A 23 and Athe supporting bar 22; and, the bind# 80ing posts 24' arealso provided with suitable washers between thesupporting bar and the -nuts onv the binding 'posts forv .properlinsulation. 1; 1

The] permanent magnet 21 Ais provided 85 with pole pieces 26,. 27 whichare preferably formed and secured Wholly within the per-4 manent .magnetthat, is.' to sa the sides' of the pole pices lare bent. v su'stantially "at right angles'fft'o' the body 'orklbase portion Q0 withthe v'endszof the base ortion bent out. Werdlyin/opposite directions 'tothe sides and forced into clamping 'relation' with the sides of thepermanent magnet adjacent-to the ends so aslto hwf'the pole pieces disf95 posed .entirely within 'thepermanent magl26', 27 arevdsposedy towardeach other'and in' slight ,spaced rel lation'. The pole pieces receivean. eli-*sc tloi magnet4 or coil 28 which is preferably of 10o the-oblon.fomationfshown in Figures 2 and '.5, with the flat sides .Hush with theinnerl sides of the pole pieces, so that the core of the coil or passagethx-ou h the coil willbedisposed at a pomt coincident with A the spacingbetween theopposi-ng pole pieces The core of the-magnet is preferably ofsome1non-magnetic material and in the preferred embodiment of mylinvention is of the general configuration shown atl 29 lin Figure 5`sothat the space within the"core 2S is adapted to receive .the holdingmember 430 shown in Figure 7.

The support holding member 30 consists of a suitable plate, the oppositesides Whereof arebent at yright angles to the body portion and thereforeinto parallel relation as shown at '31",' 31; and these sides extendslightly beyond the body portion to provide the shoulders 32. Theseshoulders extend in between the opposing pole pieces 26; 27,-

-With the ends of thepole pieces resting thereon,y as clearly shown inFigures 2 andarmature 34 shown indetail in Figure 8. .The Width ofthearmature is such that itl may fit in between the bent sides 31, 3l of Y.T

the polefpiecej separator a.nd support vholding member 30.

; .T-,he 'armature 34 is made 'of thin sheet f material andin order thatvibration within ytliearmatui'e itself may be eliminated,

` armature is provided with a longitudinally disposed rib orvrigidifying Ysurface l35. 'One endoffthe armature 34' is sliownj'provided' is "connection 'viviththe stylus rod or pin i' '37 f hifch issecured to 4 the armatureso as to| ansmit the vibrations' of thearmature to a stylus The armature 34, at opposite sdes, is provided withopposing slits adapted lto receive the y ei'ils of aI bridge or feather3 9 Lmade of thinfslieet material.

for the farmature.

- stylus-roc 37.

The ends "offtheifath'er-or'fbridge extend toward one f longitlid'inalside ofthe bridge and are disposedthrough the slits in the armature,with y 'the'protruding ends bent in opposite direc` tions on theopposite side of the armature; `Thfe bridge orffea'tlier is adapted tofit into t'heslot 33 vof lthe pole piece separator mermber 30andprovide'a rocking or tilting point rator member 3l) comes intocontact with one side'of the core 29, as clearly shown 1n far insertionthrough the slot 33 and the ar-k mature therefore maintained inproper-poi sitiong'v dropping of the armature towardiv the yoppositeside of' the coil-core boing pre-` vented b reason of -the connectionwith The stylus bar 38 which is' made of suitable andeomparatively thinsheet metal is .provided preferably With a longitudinal rib orrigidifying surface 40, see Figure 3, to

prevent lateral flexing of the stylus ban. Adjacent one end, the ,stylusbar is offset or given asomewhat angular formation, as

shown at 4l in Figure 3, so as to provide aV As the polepiece sepa- 17at apoint adjacent to the opening 19,at -the center' of the plate asclearly shown in Figure' 3. The stylus bar 38, at a point adjacent toWhere it is connected with the rod or pin 37, is shown provided with ashort arm 44, see Figure 4, which will prevent lateral movement of thestylus bar at the point of connection With the stylus bar or pin 37. Theend of the short arm 44 is suitably connected to the base plate or disc17, as shown at 45 in Figure 4; it being understood that the short armor extension 44 is of thin rcsilient sheet material in orde-r thatproper movement of the stylus bar 38, induced by tlie armature 34through stylus pin or rod may ltake place.

' stylus 42 is shown preferably in the a threaded pin, see Figure 3,with the inner end flared or formed of thin sheet metaljivhicli restsedgewise in the notch in e. 'the stylus bar 3S; the inner end of thestylus'. being formed as described to permit 'lateral flexing orvibration of thc stylus, namely in -a direct-ion longitudinally of thestylus bar 3 8. The'stylus 42 is connected to the apex 'ofan innercone/46 which is preferably of sheet metal and which in turn is mountedon or provided with resilient posts or supports 47; In the constructionillustrated in Figures 2, 3`and 4, the posts 47 consist of y'equallyspaced apart and adapted to permit yibration of tlie'c'onc inducedthrough the action ofthe'stylus 42. The stylus 42 is clamped to the cone46 by suitable means, as

for example the nuts 49 screwed on the sty- 'lus above and beloyv thecone 46, as shown `'in' Figure The'spring posts 47 are suite ablysecured on the annular shoulder 18 of dished face ofthe base plate ordisc 17.

`Arranged in spaced relation with the inner cone 46 and mounted on thestylus 42 is an amplifier cone 50 which may be of suitablepaper oryfiber and4 of suitable dimensions. The amplifier cone 50 is secured inplace by .being clamped between a pair of cone discs 51. The cone discsare of thin 'sheetmaterial and of suitaljle dimensions and are slightlydished so tiat the perimeters will grip the amplifier -cone 50circumferentially at a vpoint removed from the center of the cone 50instead of at the apex of the amplifying cone 50 and therefore nearer tothe point where the vibrations are set up in the amplifying cone 50. Theinner ycone disc `the base plate 17 as vshown in Figure 4 and yareytherefore disposed inwardly over the 'Figures 3 and 5, it vis apparentthat thegf bridge or feather 39`will be held from too] 51 rests on the-nut49, while' the outer cone disc is held in place on theend of thestylus 42 by means of a n ut 52.

The stylus 42, as-is apparent from the' ,construction shown in Figure 3,transmits vibration to all of the cones and by mount.

ing the'amplifier cone in the manner shown and described, possibility ofdistortion of the inner cone 46, when fastening the amplifier cone-'onthe ,stylus is prevented-as would be the case if the amplifier cone 50was clamped immediately on and i-n contact with cone 46- and held inplace -by the outer disc vcone l. If theampliier cone 50 was placed onthe cone 46 and' clamped in-I place by the outer cone disc 5l and nut52, there would be great possibility of distortion of the inner cone 46,with the result that theunit would be thrown out of adjustment, itsfunctioning hampered and the proper tone qualities of the unitmaterially affected. With the'construction as shown in the drawings,pressure on the Vinner cone 46 by the amplifier cone and its'clampingdisc' Acones is avoided.

In Figure 10 I illustrate a modification of the inner cone 46; the4modification involving a singlepiece memberfcomprising the cone portion53 formed integral with the spring supports or legs 54 which are bentinto the angular formation shown and with the free ends bent outwardlyas shown at 55. These apertured ends 55 are adapted to be 'secured' onthe shoulder adjacent the outer perimeter ofthe supportingplate ordisc'17 in the manner previously stated.

I have shown what I believe to be the best embodiments of my invention;the same 'having been described in ter-ms employed merely as terms ofdescription and -not as terms of limitations as structural modificationsare possible' and may be made without, however, departing from thespirit of my invention.

What I claim is:M

1. A device of the character described, comprising a supporting plate, apermanent magnet placed on one side ofthe plate, pole pieces secured -tothe ends ofthe magnetin opposing relation and within the magnet,

a coil mounted within the pole pieces with the core of the coill'alignedwith the spacing between the pole pieces, an armature tiltably mountedin the core and provided with an extension extending beyond one ofthesides of the pole (pieces, a stylus bar secured at one end on sailsupporting plate and pro'- vided with a notch, a rod intermediate oflthe eirtension of the armature and lone end of said stylus'bar andconnectedthereto a 'stylus mounted in the notch ofthe sty us 'taganamplifying cone mounted on the stylus and means/whereby the amplifyingcone is 's cured on the stylus and clamped at a pon removed from theapexthereof. 2. In ay device of thecharacter'described,

to thes'tylus, and an amplifying cone secured to the stylus in spacedrelation with said first mentioned cone.'

-3. In a device,`of'the character described, a supporting member, astylus barmounted at one end on said member, said stylus bar being ofthinsheet material andprovided with a rig-idifying surface disposedlength- `wise thereof, a stylus having a thin iiattened end disposedtransversely of the stylus bar and mounted thereon whereb rockin of thestylus is prevented and exing o stylus in a direction lengthwise of thestylus bar permitted, and sound radiating means secured to the outer endof the stylus.

4. In a device of the character described,.- a supporting member, astylus bar of thin sheet material with one end thereof secured in placeon :said supporting member, the `z Astylus bar adjacent to the pointof'mounting being formed toprovide asocket, a stylus.

the i' providedvwith a thin sheet inner end mounta ed inthe socket ofthe stylus bar, said inner endbeing arranged to permit iiexingof thelstylus in adirection lengthwise ofthe stylus bar, a cone,'the perimeterwhereof'. is provided with spring supports whose outer ends are securedto the supporting member and the cone held in 4spaced relation with saidmember, the apex of. the cone being apertured for passage'of the stylustherethrough' and beingv clamped to .the stylus, a radiating coneapertured at-its apex for passage of thestylus, and clampin meansdisposedon the inner and outer si` es of said cone and adapted to gripthe latter circumferentially at a point removed from the apex.

5. In a device of thecharacter described, a supporting plate, :a :thin'sheetstylusbar mounted edgewise on the supporting j plate and providedwith a .rigidifying surface lengthwise thereof, 'a stylus pronided witha thin iiexin end secured von the stylus bar, and radiating meanssecured to the stylus.

6. In a device ofthe character described,

.a supporting plate,a bracket on said plate a stylus. bar secured,atfome end to ,sai

bracket, a stylusl provided with a flexing end' securedfon' `thestylus-bami and Aradiating .means secured to the stylus.

, '7. -In aff device of the character descrilried,`

a supporting member, arixin'ner, cone liyieldingly mounted on and 1nspaced relation 'with the member, a stylus disposed through portingmember.

the apex of the cone and secured thereto,

an outer cone arranged in spaced relation with the inner cone andmounted adjacent` toits apex to-the stylus, and means secured to thestylus whereby the outer cone is clamped in place and distortion of theinner cone prevented.

8. In a device of the character described,

ya stylus provided with a thin ared` end.

mounted Aedgewise on the stylus-bar with l i said end arrangedtransversely of the stylusbar, a radiating lcone, and means wherebylsaid cone is gripped at a point removed from its apex and secured tothe stylus.

l0.' A sound reproducing device comprising a supporting plate providedlwith an opening, `a permanent magnet secured to said plate, pole-piecessecured vto the ends of said magnet and arranged wholly within themagnet, a coil arranged within the opposing pole-pieces, an armaturearranged within the coil and provided with an exten.- sion disposedbeyond the sides of thev coil Vand the pole-pieces, abridge arrangedtransversely ofthe armature and within the coil, a stylus-barmounted atone end on said plate while the opposite end is provided. with alaterally disposedA arm secured to said plate, a stylus-rodl secured atone end to the armature extension and disposed through the opening insaid plate with the other end s ecured 'tetue stylus-bar, a stylusvprovided with a thin dared end arranged transversely of and secured .tothe stylus-bar, and

fying means vsecured to .said stylusy,

1l. A sound reproducing dev-icejbomprising a supporting member, apermanent magnet arranged on oneside of-said" supporting member, aclamping bar whereby the magnet is secured 'to said member, said bar:being provided with terminal posts, pole-pieces arranged withinjthemagnet andsecured thereto, a coil within the pole-pieces, a pole-pieceseparator arrangedwithin the coil, an armature within the coil-andhaving a portionl disposed beyond the outer sides of the ,coil' and thepole-pieces, a bridge Aintermediateof one side of the armature and saidpolepiece separator,a stylus-bar arranged edgewise on the opposite sideof said supporting member with one end provided iwith a laterallydisposed resilient arm, a stylus-rod intermediate of said armatureportiontand the end of the stylus-bar'provided with said arm, a stylushaving a thin iared end mount-l ed edgewise on and transversely of thestylus-bar, an inner cone securedat its apex to said stylus and providedat its perimeter with resilient supporting portions secured to saidsupporting member, an outer cone arranged in spaced relation with theinner f cone, and means whereby said outer cone is clamped at a distancefrom its apex and secured to said stylus.

12. In a device of the characterl described,

a supporting plate, a stylus-bar secured at one end on said plate, astylus mounted at oneend on saidstylus-bar, an inner cone resilientlysupported on said plate above the stylus-bar and operatively connectedat its apex to the stylus which extends therethrough, an outer conearranged in spaced relation with the inner cone, and means y wherebysaid outer cone is gripped at a4 distance removed from its apex andsecured to the stylus.

I HERMAN C. MUELLER..

